1. Field of the Invention
The present invention relates to techniques for determining power consumption in a computer system. More specifically, the present invention relates to a method and apparatus for generating a dynamic trace of power consumption in a computer system without using voltage/current transducers.
2. Related Art
Large businesses often maintain datacenters containing dozens or even hundreds of servers that provide various computational services. Since excess heat can cause premature failure of components within servers, providing sufficient cooling capacity to remove the heat generated by these servers is a primary concern for managers of these datacenters.
At the present moment, large datacenters typically over-provision cooling capacity. More specifically, large datacenters typically provision cooling capacity by adding up the faceplate power ratings for each server in the datacenter and then providing sufficient cooling capacity to meet this estimated maximum level of power consumption. Typically, the faceplate power rating is higher than it is possible to achieve because the faceplate power ratings are extremely conservative estimates of the maximum theoretically possible power consumption of the individual components and the field-replaceable units (FRUs) within a server.
Note that the faceplate power rating is typically determined by adding up the power rating of each individual component and each FRU within the server. Therefore, the conservatively high power rating estimates for these individual components and FRUs is reflected in the faceplate power rating.
Furthermore, average server utilization factors are low. As a result, datacenters are being designed with a large amount of maximum cooling capacity, even though the actual cooling requirements may never exceed half of the maximum cooling capacity. Thus, it is desirable to be able to accurately measure the dynamic power consumption of servers to prevent needless and expensive over-provisioning of cooling systems for the servers.
One technique for measuring the dynamic power consumption of a server is to place a hardware power monitor between an external power supply and the server. Unfortunately, a hardware power monitor is expensive, typically costing many thousands of dollars. Furthermore, a hardware power monitor only measures the total power entering the server and hence cannot report on the power consumption of the individual components within the server.
Another technique for measuring the dynamic power consumption of a server is to monitor voltage and current signals reported by sensors in the power supply to calculate the dynamic power consumption of the server.
Unfortunately, not all servers have voltage and current sensors in their power supplies. Hence, for these types of servers, the only way to measure power consumption is to use a hardware power monitor.
What is needed is a method and an apparatus for measuring power consumption in a computer system without the problems described above.